Most agricultural vehicles rely on substantial air cooling for their engines, drives, even air conditioning systems. Since, however, these vehicles typically work in fairly dusty and dirty circumstances, it is necessary to filter the air before running it over or through the various heat exchangers the vehicle might have.
Accordingly, it is standard practice to form the air intake filter as a perforated dust screen centered on an axis and preferably shaped having an axially directed perforated end and a radially directed perforated side. The dust screen is rotated about its axis and a cleaning device is provided which covers a typically pie-shaped segment of the dust screen, so that each time the dust screen rotates it passes through the cleaner and in theory any particles on outer phases of the dust screen are removed.
U.S. Pat. No. 6,248,145 describes such rotary dust screen for a cooling unit of an agricultural vehicle. The rotary dust screen is provided with a brush assembly whose bristles engage an inner side of the cooling unit housing. Via these brushes, entrance of contaminants into the cooling unit via an edge of the rotary dust screen is prevented. The rotary dust screen is driven via a belt that engages with an outer end of the rotary dust screen, which belt is driven by a rotary actuator.